1. Field of the Invention
The present invention relates to a heat exchanger in which a heat supply medium exchanges heat with a heat recovery medium, and particularly to a heat exchanger with improved heat exchange efficiency.
2. Description of the Related Art
As a heat exchanging means, various types of heat exchangers in which heat of a heat supply medium is transferred to a heat recovery medium have been proposed. For example, Japanese Patent Application JP2003-211945A (particularly paragraphs 0032-0035, FIGS. 1 and 2) discloses a heat exchanger in which a heat exchange part has a heat recovery medium pipe with folded fins carrying oxidation catalyst thereon. In this heat exchanger, a mixed gas of hydrogen and oxygen is supplied to the heat exchange part, where the mixed gas is reacted in the presence of the oxidation catalyst. As a result, heat is generated (a heat supply medium is produced) and the generated heat is transferred through the fins to the heat recovery medium passing through the pipe. Japanese Patent Application JP2000-193323A (particularly paragraphs 0017-0018 and FIG. 1) discloses a heat exchanger in which a heat exchange part has pipes surrounded by a plurality of plate fins with the adjacent fins being disposed with a predetermined space therebetween. In this heat exchanger, gas is burnt in a combustion part and then allowed to flow between the fins, so that the heat of the combustion gas is transferred to a heat recovery medium passing through the pipe.
However in the conventional heat exchangers disclosed in the above documents, the heat supply medium channel is located outside the heat recovery medium channel, and therefore the generated heat in the heat supply medium is undesirably excessively released from the heat supply medium channel to the external system. Consequently, a large amount of thermal energy is lost and thus heat exchange efficiency becomes low.
Also in the conventional heat exchangers, heat transfer conditions between the heat supply medium and the heat recovery medium vary depending on the part in the exchanger, resulting in unevenness in temperature of the heat recovery medium. This also contributes to lowering of thermal exchange efficiency.
Therefore, it would be desirable to provide a heat exchanger which can solve the above-mentioned problems by attaining excellent heat exchange efficiency.
Illustrative, non-limiting embodiments of the present invention overcome the above disadvantages and other disadvantages not described above.